Energy saving roof

ABSTRACT

A roof has an outer surface with a first color under a first environmental condition and a second color under a second environmental condition. The outer surface is capable of both changing from the first color to the second color and from the second color to the first color.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

FIELD OF THE INVENTION

This invention relates to a roof or surface that changes hue when exposed to varying temperatures and/or light intensities.

BACKGROUND OF THE INVENTION

A traditional building's roof is often exposed to more sunlight than any other portion of the building. In cooler climates or during the winter months this may not be a bad thing as the solar energy absorbed by a roof can provide some amount of desired heating to the building. More often than not this desired heating is very much outweighed by the undesirable heating that occurs in the summer months when the sun's rays are more intense and are extant over a longer portion of a 24 hr period than in the cooler months. The energy costs to cool down buildings could be greatly lessened in some instances if the heat generated by a dark roof during the warmer months could be diminished. A roof that changes from a darker hue/color in cooler weather to a lighter hue/color in warmer weather would be desirable in that a darker roof in cooler weather could increase the temperature of the structure, thus lowering energy costs. Energy conservation is of great importance as it reduces the amount of fossil fuels used and lessens dependence on imported oil while at the same time lowering energy costs. There is a need for a roof that lowers energy usage and costs as the seasons change.

The instant invention as disclosed within this application, provides a roof system that fills this need. The art referred to and/or described within this application is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.

All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.

Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.

A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.

BRIEF SUMMARY OF THE INVENTION

In at least one embodiment of the invention, a roof comprises an outer surface having a first color under a first environmental condition and a second color under a second environmental condition. The outer surface can have the capability of both changing from the first color to the second color and from the second color to the first color.

In at least one embodiment, the first environmental condition is selected from the group consisting of temperature, light level, and any combination thereof.

In at least one embodiment, the second environmental condition is selected from the group consisting of temperature, light level, and any combination thereof.

In at least one embodiment, the outer surface comprises a thermochromatic paint.

In at least one embodiment, the outer layer is a laminate comprising thermochromatic material.

In at least one embodiment the first color is substantially darker than the second color (darker here assumes the same radiative/light source at the same intensity on both colors). As an example, a first color is extant in cooler temperatures of between about −120 and 65 degrees Fahrenheit, and the second color is extant in warmer temperatures of between about 65 and 150. The darker color here can also include the color that absorbs more energy from the radiative source to which the surface is exposed. Thus, for example, a monochromatic light source striking a surface having that very same monochromatic color will absorb more energy than a deeper hue of another color that is not. Thus, in some embodiments at a certain temperature/radiative intensity a roof can change color to even a deeper hue of a different color in order to lessen the heating of a surface. It should be noted that when

In at least one embodiment, the roof transitions abruptly from a first color to a second color at a threshold temperature.

In at least one embodiment, the roof gradually transitions from the first color to the second color with a rise in temperature.

In at least one embodiment, the roof has an outer surface which comprises (a) one or more electron-donating, chromatic organic compounds selected from the group consisting of diaryl phthalides, aryl phthalides, indolylphthalides, polyarylcarbinols, leucoauramines, acrylauramines, arylauramines, rhodamine B lactams, indolines, spiropyrans, fluorans, thiofluorans, phenothiazines, triphenylmethanes, diarylarylfurans, spiroxanthenearylfurans, and chromenoindoles, (b) one or more compounds capable of reversibly accepting electrons of said organic compound selected from the group consisting of phenolic hydroxy group-containing compounds and derivatives thereof and carboxyl group-containing compounds and derivatives thereof, (c) one or more compounds controlling the temperature and sensitivity of coloration/decoloration of said thermochromatic material selected from the group consisting of alcohols, esters, ketones, esters, acid amides and carboxylic acids, the ratio of each component to others (a):(b):(c) being 1:0.1 to 10:1 to 100 by weight, and (d) one or more radical cationic compounds selected from the group consisting of N-radical cationic, P-radical cationic, O-radical cationic and S-radical cationic compounds having aromatic ring(s), in an amount of from 0.01 to 5 parts by weight per 1 part by weight of said electron-donating chromatic organic compound, said radical cationic compound interacting with said electron-donating, chromatic organic compound to stabilize said compound, resulting in a thermochromatic material with an improved resistance to light.

In at least one embodiment, the roof has roof panels that have an outer surface as described in the paragraph immediately above directly disposed thereon.

In at least one embodiment, the outer surface is disposed on a membrane disposed on the roof panels.

These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for further understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there is illustrated and described embodiments of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

A detailed description of the invention is hereafter described with specific reference being made to the drawing.

FIG. 1 is top view of a representative embodiment of the invention.

FIGS. 2 a-2 c are side cross-sectional views of an embodied roof.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. It should be noted that the terms “cooler temperature” and “warmer temperature” are relative. For example, in some embodiments the warmer temperature may be 32 degrees Fahrenheit while in other embodiments the cooler temperature may be 65 degrees Fahrenheit. Generally, cooler temperatures may be between about −130 and 75 degrees Fahrenheit and warmer temperatures may be between 10 and 200 degrees Fahrenheit. These ranges are given primarily with regard to possible outdoor temperatures. In other embodied applications of this invention the ranges may be substantially colder than the cool temperatures given and/or substantially hotter than the warm temperatures given. Given the same environment and a color transition that occurs due to a change in temperature, the term “cooler temperature” is associated with a temperature cooler than that associated with the term “warmer temperature”.

It should be noted that the terms “lesser light intensity” and “greater light intensity” are relative to one another. For example, in some embodiments the greater light intensity on the surface may be 1.5 kW/m² or greater particularly if the surface is in manufactured light while the lesser light intensity is less than this. In other embodiments the greater light intensity on the surface may be 0.75 kW/m² or greater; or 0.25 kW/m² or greater. The lesser light intensity being less than the greater light intensity in each embodiment and moving from the lesser light intensity to the greater light intensity results in a change in surface coloration. Throughout the application the term thermochromatic should be recognized to mean having a color at one temperature that is different than the color at a different temperature. Unless heat and light intensity are distinguished between, thermochromatic is also meant to include the meaning of having a color when exposed to one light intensity that is different than the color at a different light intensity. In some embodiments there are multiple color changes depending on the characteristics of the thermochromatic properties of the surface with regard to temperature or light intensity. It should be noted that in other embodiments the greater light intensity can be between 1.5 and 10 kW/m². In some embodiments between about 10 and 100 kW/m²; and in other embodiments between about 100 and 1000 kW/m².

In some embodiments it is desirable that the roof remain a darker hue in warm temperatures such as on a cloudy day. In such an embodiment, the light from the sun is not strongly reaching the roof thus the roof is not heating up. For aesthetic reasons or for some other reason it can be desirable for the roof to remain darker. Thus in some embodiments, the light intensity must also reach a threshold intensity before the roof changes color. And in some embodiments the light intensity alone can create a change of surface coloration.

For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.

In FIG. 1 a top view portion of a representative roof 10 is shown. In this figure the roof has shingles 15. The shingles 15 can be made entirely of a thermochromatic material. In other embodiments the thermochromatic material is applied to the shingles.

In FIG. 2 a the thermochromatic material is applied to multiple shingles 15 as a coating 17 that extends over multiple shingles 15. Here the shingles are disposed on a roof substrate 20. The coating 17 could be applied after the construction of the shingles 15 and/or after they are applied to the roof substrate 20. In some embodiments the shingles are themselves the substrate. The coating can be a fluid (e.g. paint), membrane, powder or any combination thereof that is applied to the shingles 15. The shingles can be of any size that would be appropriate for roof construction. The length and/or width can range from less than 4 inches to more than 100 ft. In some embodiments the shingles 15 are fabricated as a sheet comprising multiple shingles per sheet. In some embodiments the sheet has an actual overlapping of shingles wherein the shingles are bound together to form the sheet. In some embodiments the sheet is made to appear as if it comprises multiple shingles wherein it is actually of single piece construction; in some embodiments sheets made to appear as if they comprise multiple shingles are formed together.

In some embodiments as in FIG. 2 b, each of the shingles 15 has its own thermochromatic coating 17. The coating can be a fluid (e.g. paint), membrane, powder or any combination thereof that is applied to each of the shingles 15. The sizing of these shingles 15 can be as those in the paragraph above.

The coating 17 can be applied to roof systems including those of asphalt, metal, membrane, slate, tile, stone, and/or plastic.

In FIG. 2 c the coating 17 is in the form of a shingle 15 itself. In this embodiment the thermochromatic coating is not applied to a shingle it is a part of the shingle composition itself.

Though the roof 10 in FIGS. 2 a-2 c illustrate the overlapping of shingles 15, this overlap is not necessary. In some embodiments the roof has no overlapping shingles 15. Moisture and/or sunlight can be reduced by the sealing of cracks between shingles 15 or by sizing the shingles such that there are no cracks as one piece of shingle covers the entire roof or at least a portion extending from the top of the roof to the bottom of the roof. In instances where the roof is substantially flat an overlap need not exist though in some embodiments an overlap does exist. The roof 10 can have a base/substrate 20 of one piece construction.

The thermochromatic coating 17 can also act to seal the roof as well. In some embodiments the thermochromatic material is added to a sealant or paint to form a continuous roof surface that seals cracks or spaces in the substrate 20.

Dyes, paints, and/or inks having liquid crystals that are microencapsulated in the form of a suspension can be used as a part of the thermochromatic surface. After absorbing a certain amount of light or heat, the crystallic or molecular structure of the pigment can reversibly change in such a way that it absorbs and emits light at a different wavelength than at lower temperatures. This change in color can result from selective reflection of certain wavelengths by the crystallic structure of the material, as it changes between the low-temperature crystallic phase, through anisotropic chiral or twisted nematic phase, to the high-temperature isotropic liquid phase.

During the twisted nematic phase the molecules can orient in layers with regularly changing orientation, which gives them periodic spacing. The light passing the crystal can undergo Bragg diffraction on these layers, and the wavelength with the greatest constructive interference can be reflected back, which is perceived as a spectral color. A change in the crystal temperature can result in a change of spacing between the layers and therefore in the reflected wavelength. The color of the thermochromatic liquid crystal can therefore continuously range from non-reflective (black) through the spectral colors to black again, depending on the temperature. Though multiple liquid crystals can be used two examples are cholesteryl nonanoate and cyanobiphenyls.

After absorbing a certain amount of light or heat, the crystallic or molecular structure of the pigment reversibly changes in such a way that it absorbs and emits light at a different wavelength than at lower temperatures.

It should be noted that the surfaces within this application can be either interior or exterior. In cooler temperature a darker interior floor may be desirable as solar energy can heat the floor as well as reduce glare. In warmer temperature a lighter interior floor may be desirable. Interior surfaces having exposure to the suns rays or artificial lighting may also benefit from a surface that changes color due to temperature.

These energy saving roofs can also be formed on vehicles such as mobile homes, pop-up trailers, trucks, tractors, golf carts, and cars. This can be done in a similar way as with the more stationary roofs for buildings. The thermochromatic material can be applied after general construction as a paint or the like. The thermochromatic material can also be constructed on the vehicle when manufactured. This thermochromatic material can also be used in tents, tarps and the like. Among other uses, this could be helpful on the farm or while camping. The materials can also be applied after initial manufacture.

The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. The various elements shown in the individual figures and described above may be combined or modified for combination as desired. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”.

Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim 1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below.

This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto. 

1. A roof comprising an outer surface, the outer surface having a first color under a first environmental condition and a second color under a second environmental condition, the outer surface capable of both changing from the first color to the second color and from the second color to the first color.
 2. The roof of claim 1 wherein the first environmental condition is selected from the group consisting of temperature, light level, and any combination thereof.
 3. The roof of claim 2 wherein the second environmental condition is selected from the group consisting of temperature, light level, and any combination thereof.
 4. The roof of claim 1 wherein the outer surface comprises a thermochromatic coating.
 5. The roof of claim 1 wherein the outer layer is a laminate comprising thermochromatic material.
 6. The roof of claim 1 wherein the first color is substantially darker than the second color, the first color extant in cooler temperatures of between about −120 and 65 degrees Fahrenheit, the second color extant in warmer temperatures of between about
 7. The roof of claim 1 having a transition from the first color to the second color that occurs at a threshold temperature.
 8. The roof of claim 1 having a gradual transition from the first color to the second color with a rise in temperature.
 9. The roof of claim 1 wherein the outer surface comprises (a) one or more electron-donating, chromatic organic compounds selected from the group consisting of diaryl phthalides, aryl phthalides, indolylphthalides, polyarylcarbinols, leucoauramines, acrylauramines, arylauramines, rhodamine B lactams, indolines, spiropyrans, fluorans, thiofluorans, phenothiazines, triphenylmethanes, diarylarylfurans, spiroxanthenearylfurans, and chromenoindoles, (b) one or more compounds capable of reversibly accepting electrons of said organic compound selected from the group consisting of phenolic hydroxy group-containing compounds and derivatives thereof and carboxyl group-containing compounds and derivatives thereof, (c) one or more compounds controlling the temperature and sensitivity of coloration/decoloration of said thermochromatic material selected from the group consisting of alcohols, esters, ketones, esters, acid amides and carboxylic acids, the ratio of each component to others (a):(b):(c) being 1:0.1 to 10:1 to 100 by weight, and (d) one or more radical cationic compounds selected from the group consisting of N-radical cationic, P-radical cationic, O-radical cationic and S-radical cationic compounds having aromatic ring(s), in an amount of from 0.01 to 5 parts by weight per 1 part by weight of said electron-donating chromatic organic compound, said radical cationic compound interacting with said electron-donating, chromatic organic compound to stabilize said compound, resulting in a thermochromatic material with an improved resistance to light.
 10. The roof of claim 9 wherein the outer surface is a coating.
 11. The roof of claim 10 wherein the coating is a powder coating selected from the material group consisting of epoxies, polyesters, urethanes, nylon, vinyl, polyethylene, and any combination thereof.
 12. The roof of claim 10 wherein the coating is a paint (either sprayed or brushed).
 13. The roof of claim 1 having roof panels, the outer surface disposed directly on the roof panels.
 14. The roof of claim 1 having roof panels, the outer surface disposed on a membrane disposed on the roof panels.
 15. The roof of claim 4 wherein the coating is a powder coating selected from the material group consisting of epoxies, polyesters, urethanes, nylon, vinyl, polyethylene, and any combination thereof.
 16. The roof of claim 4 wherein the coating is a paint.
 17. The roof of claim 1 wherein the outer coating is of uniform construction (define).
 18. The roof of claim 1 wherein at least one portion of the roof maintains the substantially same color under the first environmental condition and the second environmental condition.
 19. A surface of a building comprising an outer surface, the outer surface having a first color under a first environmental condition and a second color under a second environmental condition, the outer surface capable of both changing from the first color to the second color and from the second color to the first color.
 20. The surface of claim 19 selected from the group consisting of decks, porches, walls, patios, driveways, parking pads, parking lots, interior floors, and walkways. 